1. Field of the Invention
The present invention relates to an engine operated machine system including an engine and a working machine driven by the engine, which are accommodated in a box-shaped case. In particular, the present invention relates to an improvement in an engine operated machine system suitable for a case where a waste-heat recovery unit for recovering the waste heat of the engine is accommodated in a case, as in a cogeneration system.
2. Description of the Related Art
In solving environmental problems, recovery and utilization of waste heat discharged from an engine by a cogeneration system and the like has recently attracted public attention. In an engine operated machine system including a waste-heat recovery unit, such as a cogeneration system, all devices that include an engine, a working machine, and a waste-heat recovery unit are completely covered by a box-shaped case in consideration of the operational noises emitted to the surrounding environment, as disclosed in, for example, Japanese Utility Model Publication No. 7-46741.
In the engine operated machine system disclosed in Japanese Utility Model Publication No. 7-46741, a ventilating fan and a ventilation port are provided in order to cool the devices within the case. In terms of recovering the waste heat discharged by the engine, the lowered temperature within the case leads to a heat loss, and energy needed to drive the ventilating fan results in an overall increase in energy consumption. In making the overall structure compact for accommodating the electrical equipment needed to control the engine and the working machine within the box-shaped case, the thermal influence from the engine and the working machine must be prevented from affecting the electrical equipment. However, Japanese Utility Model Publication No. 7-46741 does not disclose any such thermal influence preventing measures.
In contrast, the Applicants of the present invention have already achieved a cogeneration system, wherein the inside of a case is vertically divided into an upper chamber and a lower chamber to cut off the flow of air. An engine, a working machine, and a waste-heat recovery unit are accommodated in the lower chamber, while components, such as an electric control device needed to avoid the thermal influence from the engine and working machine, are accommodated in the upper chamber. As a result, waste heat from the engine is sufficiently recovered to enhance energy recovery efficiency, as disclosed in Japanese Patent Application Laid-open No. 2001-132564.
However, with the arrangement of the engine operated machine system disclosed in Japanese Patent Application Laid-open No. 2001-132564, it is difficult in some cases to appropriately maintain the temperature within the case. In addition, a partition wall is required to be disposed at a particular location in order to appropriately maintain the temperature within the case. In addition, the partition wall is disposed at a location closest to a high-temperature portion of the lower chamber. As a result, a feature to help avoid the influence of the heat transmitted to the upper chamber through the partition wall is required in response to conditions of temperature setting and the like.
It is an object of the present invention to overcome the above-described drawbacks of the Related Art.
It is also an object of the present invention to provide an engine operated machine system which easily prevents a thermal influence from affecting the components which must avoid the thermal influence in order to provide enhanced waste-heat recovery efficiency.
To achieve the above objects, there is provided an engine operated machine system including an engine, a working machine driven by the engine, and a waste-heat recovery unit for recovering the waste heat of the engine. The components of the engine operated machine system are accommodated in a box-shaped case. The box-shaped case is provided with a partition wall that partitions the inside of the case into a working-machine accommodating chamber that accommodates the engine, the working machine and the waste-heat recovery unit, and an electrical-equipment accommodating chamber. The partition wall has a draft bore which connects the working-machine accommodating chamber to the electrical-equipment accommodating chamber. The case is also provided with a cooling-air intake port connecting the electrical-equipment accommodating chamber to the outside or atmosphere, a discharge port for forcibly discharging, to the outside, air discharged from the working-machine accommodating chamber by a fan driven by the engine, and an assist fan disposed in the draft bore and adapted to be operated, in response to the temperature in the working-machine accommodating chamber exceeding a predetermined value, to feed the air in the electrical-equipment accommodating chamber into the working-machine accommodating chamber.
With the arrangement of the above-described feature, when the temperature in the working-machine accommodating chamber is equal to or lower than the predetermined value, the assist fan disposed in the draft bore is not operated and functions as a draft resistance. Thus, an excessive amount of air does not flow from the electrical-equipment accommodating chamber into the working-machine accommodating chamber, and the amount of the air forcibly discharged by the fan driven by the engine only flows from the electrical-equipment accommodating chamber into the working-machine accommodating chamber. Therefore, the temperature in the working-machine accommodating chamber is prevented from being lowered excessively, thereby enhancing the efficiency of recovery of the waste heat energy. Only when the temperature in the working-machine accommodating chamber exceeds the predetermined value does the assist fan feed the cooling air into the working-machine accommodating chamber, thereby preventing the temperature in the working-machine accommodating chamber from rising excessively. Moreover, the cooling air flows through the electrical-equipment accommodating chamber into the working-machine accommodating chamber, that is, the components in the electrical-equipment accommodating chamber are cooled by the cooling air having a relatively low temperature.
According to a second feature of the present invention, the partition wall extends vertically, and the draft bore is provided in a lower portion of the vertically extending partition wall. With this arrangement, because the partition wall extends vertically, the temperature of the partition wall itself is suppressed to be lower relative to a partition wall that vertically partitions the inside of the case so that the amount of heat transmitted through the partition wall to the electrical-equipment accommodating chamber is decreased. Therefore, it is easy to appropriately maintain the surrounding temperature in the electrical-equipment accommodating chamber.
According to a third feature of the present invention, at least the engine of the engine and working machine driven by the engine is supported on a bottom of the case with buffer members interposed therebetween, and the assist fan is mounted to the partition wall so that it blows the air within the electrical-equipment accommodating chamber toward the buffer members. With this arrangement, the air from the assist fan, which is operated in response to the temperature in the working-machine accommodating chamber exceeding the predetermined value, is blown to the buffer members. As a result, it is easy to suppress the temperature of the buffer members which are liable to be thermally influenced within an acceptable temperature range.
According to a fourth feature of the present invention, the electrical-equipment accommodating chamber has a labyrinth-shaped intake passage defined therein for guiding the air from the cooling-air intake port to an upper portion of the electrical-equipment accommodating chamber and then guiding the air through the electrical-equipment accommodating chamber to the draft bore. With this arrangement, a wall which defines the labyrinth-shaped intake passage suppresses the radiation of operational nose from the working-machine accommodating chamber through the electrical-equipment accommodating chamber to the outside by cooperating with the partition wall. The intake passage effectively dispenses the cooling air to the components in the electrical-equipment accommodating chamber and also functions as an intake silencer chamber. Moreover, rainwater is prevented from entering through the cooling-air intake port into the electrical-equipment accommodating chamber by the intake passage.
According to a fifth feature of the present invention, there is provided an engine operated machine system including an engine, a working machine driven by the engine, and a waste-heat recovery unit for recovering the waste heat of the engine. The components of the engine operated machine system are accommodated in a box-shaped case. The box-shaped case is provided with a partition wall that extends vertically to partition the inside of the box-shaped case into a working-machine accommodating chamber that accommodates the engine, the working machine and the waste-heat recovery unit, and an electrical-equipment accommodating chamber. The partition wall has a draft bore which connects the working-machine accommodating chamber to the electrical-equipment accommodating chamber at a lower portion of the partition wall. The case is also provided with a cooling-air intake port connecting the electrical-equipment accommodating chamber to the outside or atmosphere, and a discharge port forcibly discharging, to the outside, air discharged from the working-machine accommodating chamber by a fan driven by the engine. The electrical-equipment accommodating chamber has a labyrinth-shaped intake passage defined therein for guiding the air from the cooling-air intake port to an upper portion of the electrical-equipment accommodating chamber and then guiding the air to the draft bore.
With the arrangement of the above-described feature, an amount of air that is forcibly discharged by the fan driven by the engine flows from the electrical-equipment accommodating chamber into the working-machine accommodating chamber. As a result, the air flows such that the temperatures of the engine and a generator do not rise excessively. In addition, the cooling air flows through the electrical-equipment accommodating chamber into the working-machine accommodating chamber, that is, the components in the electrical-equipment accommodating chamber are cooled by the cooling air having a relatively low temperature. Further, the air having a temperature that is moderately raised as a result of being passed through the electrical-equipment accommodating chamber is supplied into the working-machine accommodating chamber. As a result, the temperature around the waste-heat recovery unit is not excessively lowered, thereby enhancing the efficiency of waste heat energy recovery. Moreover, the partition wall extends vertically and therefore, the temperature of the partition wall itself is suppressed to be low relative to a partition wall that vertically partitions the inside of the case, and the amount of heat transmitted through the partition wall to the electrical-equipment accommodating chamber is minimal. Therefore, it is easy to appropriately maintain the surrounding temperature in the electrical-equipment accommodating chamber. A wall defining the labyrinth-shaped intake passage functions to suppress the radiation of operational noise from the working-machine accommodating chamber through the electrical-equipment accommodating chamber to the outside by cooperating with the partition wall. Also, the intake passage itself effectively dispenses the cooling air to the components in the electrical-equipment accommodating chamber to cool the components, and functions as an intake silencer chamber. Further, rainwater is prevented from entering through the cooling-air intake port into the electrical-equipment accommodating chamber by the intake passage.
According to a sixth feature of the present invention, electrical equipment accommodated in the electrical-equipment accommodating chamber is mounted, in a vertical arrangement, to the partition wall in such a manner that the electrical equipment which generates a relatively large amount of heat is located in a lower position of the partition wall. With this arrangement, the air flowing through the electrical-equipment accommodating chamber finally cools the electrical equipment generating the relatively large amount of heat and then flows to the working-machine accommodating chamber. As a result, the cooling air is appropriately dispensed to the electrical equipment within the electrical-equipment accommodating chamber to appropriately cool the electrical equipment.
According to a seventh feature of the present invention, a vertically extending narrow passage section is defined in the middle of the intake passage. Also, a comb tooth-shaped heat-radiating plate is provided in the electrical equipment that generates the relatively large amount of heat and protrudes into the narrow passage section with a plurality of vertically extending passage portions therebetween. With this arrangement, most of the cooling air flowing to the working-machine accommodating chamber is blown to the heat-radiating plate, thereby effectively cooling the electrical equipment which generates the relatively large amount of heat. The transmission of the heat from the electrical equipment to the case is also inhibited.
According to an eighth feature of the present invention, an assist fan is disposed in the draft bore and is adapted to be operated, in response to the temperature in a lower portion of the working-machine accommodating chamber exceeding a predetermined value, to feed the air in the electrical-equipment accommodating chamber into the working-machine accommodating chamber. With this arrangement, when the temperature in a lower portion of the working-machine accommodating chamber is equal to or lower than the predetermined value, the assist fan disposed in the draft bore is not operated and functions as a draft resistance. As a result, an excessive amount of air does not flow from the electrical-equipment accommodating chamber into the working-machine accommodating chamber. Also, the amount of air that is forcibly discharged by the fan driven by the engine only flows from the electrical-equipment accommodating chamber into the working-machine accommodating chamber. Accordingly, the temperature in the working-machine accommodating chamber is prevented from being excessively lowered. Only when the temperature in the lower portion of the working-machine accommodating chamber exceeds the predetermined value does the assist fan feed the cooling air into the working-machine accommodating chamber, thereby preventing the temperature in the working-machine accommodating chamber from being excessively raised.
According to a ninth feature of the present invention, at least the engine of the engine and working machine is supported on a bottom of the case with buffer members interposed therebetween. Also, the assist fan is mounted to the partition wall so that the assist fan blows the air within the electrical-equipment accommodating chamber toward the buffer members. With this arrangement, the air from the assist fan that is operated in response to the temperature in a lower portion of the working-machine accommodating chamber exceeding the predetermined value is blown to the buffer members. As a result, it is easy to suppress the temperature of the buffer members, which are made of a mount rubber or the like and are liable to be thermally influenced to within an acceptable temperature range.
The above and other objects, features and advantages of the invention will become apparent from the following description of the preferred embodiment taken in conjunction with the accompanying drawings.